Six Billion Stars in the Sky
by Chessanator
Summary: After the world ends, Diana gets a lead about where Sigma headed afterwards. Its the best gift she could have asked for; she needed to meet him again more than anything else. But now she's tangled in the web of timelines that make up Rhizome Nine. And the secrets that make up Sigma's life will weigh on her more than she can possibly imagine. (A gift for ZEcret Santa 2018)
1. Hunting for Meaning in a Worn-out World

Diana knelt by the side of the bed and adjusted the cold flannel on the patient's forehead. She sighed. She couldn't help but think about how far civilisation had fallen since the end of the world as she watched over the poor man, just barely out of his teens, who lay on the makeshift hospital bed. It was just a normal strain of influenza. Before the outbreak – even between the outbreak and the antimatter explosions – all that would have been needed as a cure was a nutritious diet, good bedrest, and kindness. But now good food was in short supply, with the humanity needing to scrabble away for every last calorie. And who knew how long it would be until the next crisis after crisis struck and every able hand would be needed to help, no matter how healthy or ill they were?

But kindness, and a kind word… That was something Diana could still provide. And she did.

After all, everything that had happened was all her fault.

As Diana stood up, adjusted her patient's sleeping position, and took his temperature, the door to the ramshackle infirmary opened behind her. Diana took in a deep breath, steeling herself to deal with the next illness or injury. But the footsteps that entered didn't sound at all urgent. And it was only one person, light on their feet: not someone who'd needed to be helped in.

"Are you okay?!" Diana called out. She paused, gathering up her equipment. "I'm sorry I'm making you wait. Just give me a moment and…"

Diana had caught the unexpected visitor out the corner of her eye. She gasped, dropping the thermometer she was holding. She didn't even notice the tinkling as it shattered on the floor; all her attention was focused on the woman who'd just entered.

"You? B-But… you're dead? You're dead! I… I'm so sorry, but… I killed you!"

"Yes. I suppose you did," Akane Kurashiki replied. She strode into the centre of the room, not caring at all the dilapidated shelving only-half-filled with randomly assorted medicine, or the makeshift beds that had been the best Diana's shelter could manage for their infirmary. "But let's talk about something far more important. Is there anywhere we can talk with more privacy?"

o-0-O-0-o

At that time of day, the common room of the bomb shelter Diana had survived in shouldn't have had anyone there. Indeed, it didn't. Akane took a seat at the table furthest from the door, sitting on the far side and watching the entrance warily as Diana made her way over to sit down opposite. When Akane was sure that no-one was entering behind them, she nodded, letting Diana speak.

Diana's voice caught in her throat for a second and a half. But then she finally forced the question out. "I don't understand. Zero's Decision Game, the executions… how are you here? How did you survive?"

Akane shook her head gently. "I'm sorry. I'd like to tell you, but I can't."

"Why not?"

"The timelines gong forward are too important. I can't risk contaminating them with unnecessary information."

Diana wasn't surprised by an answer like that. It was just like Akane had been back in D-Com, and Sigma and Phi too, back before they'd all been spirited away for Zero's Decision Game. But it still stung. "You don't want to tell me anything… okay. I can try to understand that. But then, why are you here? Why didn't you just leave me here, where I could do some good for everyone who survived?"

"That, also, depends on the timelines which are to come," Akane said. "How would you like to meet Sigma again?"

Diana couldn't help but exhale sharply at that thought. Sigma, the mysterious gentleman who'd appeared from nowhere to take his place in the Mars Mission test. Sigma, who'd been the stalwart pillar of the team Zero had insisted on naming after her. Sigma, who'd unflinchingly thrown his life and limb on the line to save Phi and Diana.

Sigma, who Diana had utterly failed right at the end.

"He survived?! Where did he go? You know where he went?" Diana asked.

The last she'd seen of him was when he had lost both his arms in the blast that had allowed Phi and Diana to escape. She's wanted to stay with him, but on reaching the surface he'd quickly been carted off to a hospital to treat his mangled limbs. Those people hadn't known how important and difficult it would be for people to stay in touch. By the time Diana had finally convinced them, it was too late. Sigma had disappeared, and the world had ended.

Diana sighed mournfully. "He let you know where went," she muttered. "He never told me."

"Naturally, I know where Sigma went," Akane said. "After all, I prepared his next step for him."

Diana's breath caught in her throat. "He made it to a shelter?" she asked.

Akane stood up, stepped around the table and headed towards the door out. But halfway there, she stopped. She beckoned Diana to follow her.

"Of a sort," Akane replied.

o-0-O-0-o

So that was how Diana found herself sitting in a shuttle as it launched on its way to the moon. G-forces had driven her back into her seat as the rockets accelerated, to the point where she could barely even move. At least she didn't have to do anything: Akane had assured her that the autopilot would take right to the landing pad of the moonbase.

So all Diana had was time, alone, to think. What would she do when she finally met Sigma again? What could she say to him about the life she'd lived between the end of the Decision Game and finding out where he's gone? And would he have forgiven her for letting her courage fail and the world end?

Diana could have let her hopes and frets spin around each other in her mind for the rest of time. But the journey to Sigma's moonbase eventually had to end. The autopilot gave an announcement ordering her to strap back in, and those restraints kept her safe and secure as the final landing rattled the entire shuttle. Then, once they were stationary, the autopilot guided her in taking and putting on a spacesuit and allowed her out through an airlock.

Then she entered the airlock of the moonbase. She had to wait until the pressure in the airlock had been brought back up to normal, but then she eagerly threw off the spacesuit and rushed for the exit. In the room on the other side, the only way forward was a small platform elevator. She got on and frantically jabbed the button, her heart pounding all the way as it slowly rose to the floor above.

And then, she saw him.

Tall, handsome, welcoming. Wearing a sleek labcoat: different to the clothes he'd worn when she'd last seen him, but it made sense given what Akane said he'd been doing in his moonbase. And he was wearing an eyepatch over his left eye and his arms had been replaced by skeletal metallic limbs, mementos of the injuries he'd taken helping Diana and Phi escape from the underground bunker.

It was Sigma. Diana had finally found him.

Her heart caught in her throat. When she spoke, as she had wanted to speak to him for so long, the words just tumbled out of her mouth, all the lines she'd practiced again and again falling aside in a rush of emotion. "My God! Sigma! It's… It's really you! It's really you. Oh God, I've missed you so, so much."

And Sigma replied…


	2. The Sum of Possibilities

_Earlier…_

It had been a month since Sigma had leapt back in time from the end of the Nonary Game. He'd known, or at least been told, that he would have to spend the next forty-five years preparing that very same Nonary Game and becoming Zero Senior. But every day there was a new reminder of how far he had to go.

None of the rooms had started with their puzzles already installed, of course. Rhizome Nine had been built to be a working moonbase, not a killing game. With no puzzles to manage and most of the base inactive they hadn't needed to install the quantum computer yet; the room that Sigma knew as the Q Room only contained the colony of termites he'd brought up from Earth. With no high-powered quantum supercomputer to keep running there hadn't been any need yet for an antimatter reactor to supply the power. And, of course, there wouldn't be any Gaulems until Sigma had designed and programmed them himself. The corridors of the Rhizome were echoingly lonely.

All of that would need to have changed by the time Sigma jumped back to the past once more. But he only had barely a clue about the process that would take. Sometimes he managed to commit himself to readying one room: the day before he'd finally gotten around to installing the computers, posters, fire extinguishers and handrail ends in the shipping crates that would eventually become known as the AB Rooms. At other times Akane would call with new orders, changing his priorities based on whatever she was up to on Earth. She had an uncanny ability to call up on exactly those days which Sigma had chosen to take off.

Today, though, Sigma had no clue what he was supposed to be doing. He felt he was supposed to be doing something, so he'd headed to the laboratory to get familiar with what he could do there. It had been the room most similar to how he'd remembered it from the Nonary Game, with all the workbenches and equipment and stores of chemicals already in place. It was obviously a room that had been incredibly important for the intended use of the facility. And Sigma knew that it would be incredibly important for him as he set up the Nonary Game, not just for the puzzle-room itself but also to produce the Soporil Beta for the wristbands, the neostigmine that would save his life in one timeline, the Axelavir that would allow the Nonary Game to finally end, and much, much more. And it would also be the place where Sigma would give life to Kyle. Sigma wouldn't forget that either.

So getting familiar with everything the lab had to offer was one of the most important things Sigma had to do. He slipped on one of the many labcoats and got to examining each and every one of the bottles of chemicals in stock. It was slow, awkward, work. Not that the motion of Sigma's replacement arms was at all clumsy – he'd have noticed too quickly during the Nonary Game if he'd been like that. But the difference between having complete imitation hands and just the steel skeleton beneath kept throwing off his instinctive distance-gauging as he grasped each flask, and he couldn't risk gripping to forcefully and shattering them.

So he didn't get the chance to examine much before an announcement blared through the facility's loudspeakers. "Alert! Space shuttle on approach to land at the Rhizome Nine landing pad."

Sigma figured that Zero Jr. – Lagomorph, as Akane had called him – would have had some cutting joke to interweave into an announcement like that. Getting around to programming Lagomorph was just one more thing on Sigma's to-do list.

After carefully putting the last bottle he'd been inspecting back in his place, Sigma headed for the Pressure Exchange Chamber. That was where whoever had brought the shuttle to Rhizome Nine would arrive once they'd landed. They would be able to operate the airlock by themselves, so all Sigma had to do was wait for them to get in.

That wait ended up being just one more reminder of how far Sigma had to go. When he'd explored the Pressure Exchange Chamber with Clover and Tenmyouji, the entire room had been grimy and well-used, with the pipes into the airlock groaning and clanging restlessly as they'd pumped the air out of the airlock or forced it back. But now, in 2029, the Pressure Exchange Chamber was practically brand-new and if he hadn't been forewarned by the announcement and by the clanging as the outside hatch closed, he wouldn't have been able to catch the slight whistle as the airlock got to work.

Eventually the airlock finished its job and the guest made their way to the platform elevator that would bring them into the main facility. Sigma watched as the elevator rose and she stepped off.

A ginger-haired lady in a red jumper and a modest skirt. She clasped her hands together demurely in front of her and gasped slightly as she saw Sigma waiting for her. Sigma opened his mouth to greet her to Rhizome Nine.

"Hi! I'm Sigma. It's a pleasure to meet you. Did Akane send you to help? Welcome aboard, if that's the case. By the way, what's your name?"


	3. Joined Hearts Disjointed Lives

"My God! Sigma! It's… It's really you! It's really you. Oh God, I've missed you so, so much."

"Hi! I'm Sigma. It's a pleasure to meet you. Did Akane send you to help? Welcome aboard, if that's the case. By the way, what's your name?"

o-0-O-0-o

Diana's all-too-heartfelt relief broke in two. "Sigma? Don't you remember me?"

Sigma just shook his head, a bemused expression on his face. Where had it gone: his brilliant calm confidence? The assurance that he knew everything worth knowing and that he'd use all his knowledge and wisdom on your behalf? Now, Sigma just seemed oblivious and lost.

"I'm Diana," she said. It was a small surrender.

"It's a pleasure to meet you, Diana," Sigma replied. He paused. "I gotta say, you do seem familiar…"

Diana's clasped hands leapt up to her chest, hope rising in her again.

"… but these days that could mean anything. Shall we go?"

o-0-O-0-o

Sigma led Diana on a tour of Rhizome Nine. They passed through several rooms, one after another: a small brightly-lit indoor garden, a library whose looming bookcases were still mostly bare, and then a room called the 'Treatment Centre', where Diana saw another familiar face.

"Phi!" Diana gasped. Phi was lying inside some sort of high-tech pod, completely motionless, her eyes closed. "Is she alive?" she asked Sigma.

He nodded solemnly. "Yeah, that's right. The treatment pod she's in is stopping the Radical-6 from progressing, somehow. It can't cure it, but… it's better than nothing."

Diana breathed a sigh of relief. At least Phi was still alive.

There were two other pods there, and two other people: one a young woman with incredibly bouncy pink hair, the other an elegant Egyptian lady. Diana wondered if they were also people who'd contracted Radical-6 who Sigma had saved. But before she could ask, Sigma had already started to head off to continue the tour. By the time Diana caught up, her vague question had already faded out of mind.

o-0-O-0-o

As Sigma continued to lead Diana on, another idea began to grow. So much about what Sigma was showing her seemed… familiar. It wasn't any particular detail that stood out to her, though the metal winding corridors definitely helped. Just the overall effect, like the facility was built with the same purpose in mind as somewhere she'd been before.

"You've had experience with moonbases before?" Sigma asked. Diana realised she had been muttering to herself, and Sigma had overheard.

Diana shook her head. "No. Not at all. I was just a nurse, before… before everything. Maybe it's just that this place is like D-Com? It was supposed to be simulating a space base, so I can understand why it might feel similar."

"You were at the Mars Mission test site?" Sigma asked, his tone rising with concern and sympathy. "I heard about what happened there. It must have been terrible. But I'm glad you made it out okay."

'You were there too!' Diana wanted to scream. But it wouldn't have helped. Sigma wasn't playing any sort of practical joke on her; he really didn't remember anything about the time they'd spent together. She recalled how when he and Phi had first met her at D-Com, they'd given a story about having come back from the future. Diana hadn't quite believed it at the time, and with it only half-remembered she could barely wrap her head about what it all might mean. But, following this Sigma so different from the one she knew, she wondered if the reason why he couldn't remember was something similar.

At least this Sigma still had the kindness of the one she knew.

o-0-O-0-o

The tour of that floor ended at a door labelled 'Director's Office'. "This is where I've been staying," Sigma explained as the door opened, revealing a neat but well-used office. In one of the side walls a panel had been turned slightly ajar, revealing a passage that probably headed to the Director's bedroom. "I've been the only one here up until now," Sigma continued, "which I guess makes me the director if anything does. And there's… you know." He shrugged.

"It looks very cosy," Diana said politely.

"The office still needs a bit of fixing up," Sigma said. "The entire facility does, really. Any chance I can ask you to help me with that?"

"Of course!" Diana replied instantly. For a moment she was bubbling with curiosity, wanting to stay the entire night with Sigma in his room and ask him about everything: everything he'd done before she'd come, everything he knew about the facility, and everything he and Akane had planned. Then she caught herself. This Sigma didn't remember her. They would have to start their relationship all over again from the beginning, and what Diana wanted to do was far too forward. "Is there a place I can sleep?" she asked instead, trying to keep the disappointment out of her voice.

"Sure. There are some cabins on the floor above which are just about liveable," Sigma said. "I'll show you where they are and help you get your luggage there."

"Thank you."

Diana didn't have to rush into things. There would be another day, and another day after that. She and Sigma had all the time in the world.


	4. Eyes that See Ears that Hear

_One Year Later…_

Sigma woke up. He started to get up out of the infirmary bed he was lying in but then a hand on his shoulder firmly but kindly kept him in place.

"Can you stay still, just a couple more seconds? Please?" Diana asked.

"Huh? What's up?"

And then, it struck him. First there was a buzzing pain, deep behind his eye socket. Then, his vision went black. And then.

"Diana!" he gasped. "You have a right-hand side!" He looked over her again. "A very attractive right-hand side, I must say."

"Hush, Sigma. You've seen my right-hand side before." But even as she said that, Diana giggled happily.

Sigma, after making sure he had Diana's permission this time, sat up and looked around the infirmary. His vision really was back to perfect now, on both sides. He'd know that would have to happen eventually, of course – his younger self hadn't noticed any differences in his vision during the Nonary Game – but Diana had managed to install his artificial eye exactly right first time.

"Oh, it was nothing," Diana said. "Most of it was just automatic. All I had to do was make sure you didn't through off the calibrations at the end by moving around too wildly."

"I have to thank you for that, at least!" Sigma knew that Diana had done a hell of a lot more, of course. The replacement eye was a highly complicated piece of technology, and Sigma only had the barest idea how it was supposed to interface with his optical nerve. But Diana wanted to be modest about it. Sigma chose to quickly change the subject. "Hey, Diana… What do you know about how I lost my eye in the first place? I know it was when I went to help out at the Mars Mission test site, but…"

The two of them had been dancing around the subject for months, and Diana hesitated before explaining. "Yes, that's right. You were one of the other participants. So when Zero II kidnapped us, you were taken as well. We both ended up in his death game together, on the same team."

Sigma was also a participant? He'd known that he'd been there, at least at the end, but from the few details he'd picked up he and Phi could just have easily arrived later. But they'd been there, at the Mission site, from the start… No wonder Diana had been so frustrated with him. She'd gotten to know his older self for the entire experiment before Zero II had arrived, and now he didn't know anything about that at all.

And Free the Soul had run their own death game with the Mars Mission participants? Did that mean that they had something else in mind, rather than just taking and unleashing the Radical-6? Sigma had no idea.

"Diana…" He paused again. It was awkward, but he had to know. "What was my older self like? The me you said participated in the Mars Mission experiment?"

"Your 'older self'…?" Diana murmured. "It's really true, then? What you and Phi told us? That you'd come back in time from the future?"

Sigma nodded. "Pretty much. It's what I'm doing here. Preparing, so we can manage to make the leap back."

"I never could believe it – trust that it was the truth – back when you… he… told us. I'm so sorry."

"Don't be." Sigma let out a conciliatory chuckle. "I didn't believe it either, when I first found out. Goddamnit, what happened to my life has just been crazy. It's hardly your fault you thought old me was wrong."

"So… about the you I knew. He was…" Diana trailed off.

"You don't need to compare us if you don't want to!" Sigma quickly exclaimed. "I shouldn't have put you on the spot like that. Sorry."

Diana wrung her hands together, but said, "It's okay. I've wanted to talk about it." She closed her eyes, reminiscing. "He was… Now I know that he was telling the truth, everything I remember seems to make it more and more obvious that he'd seen a lot in his life. He just knew where he stood, and he wasn't afraid to stand up for everyone else. I… I really respected him."

Sigma couldn't help but beam. "I guess I've got a lot to look forward to. Even more than that, if we do manage to stop the end of the world this time around."

Diana stepped away from the bed and gestured into the space on the floor she'd left for Sigma. "Let's see you get up and give that eye a try out," she said.

Sigma did just that. He stepped out of the bed and twirled around, seeing how the artificial eye dealt with sudden motion and translated it for his brain. Diana had accomplished it perfectly again, with the new eye keeping exactly in sync with the natural eye's reflexive motions. There was no way Sigma could have gotten his vision so seamless without Diana's help. "It's all good," he said with pride.

"I'm so glad," Diana replied. She looked deeply into Sigma's eyes – both of them, not preferring the natural to the artificial – before saying, "Is that everything you needed me to help you with today? I'm a bit tired, so I could just do with a nap."

"Sure." Sigma had only been lying in the infirmary all morning while Diana did the actual work, but he felt exhausted as well. "There's still forty-four years until everything comes to a head. I think we deserve a rest." As Diana took a step towards the door back towards her crew cabin, Sigma felt the urge to speak up again. "One last thing?"

"Yes?"

"Akane told me that I lost my limbs and an eye saving someone from the Mars Mission project. A woman. Diana… was that you?"

Diana spun back around and leaned into Sigma: a full bodied hug. "Yes. It was me. You saved me, Sigma! I don't know what I would have done without you."


	5. Shot to the Heart

_Two Years After That…_

Diana sat in the room in Rhizome Nine that had just recently been rechristened the 'Lounge', after the sofas she was sitting on and the bar and shelving had been installed, and the door in the wall off the main route through it had been re-fitted to be entire unobtrusive. Akane had come up to Rhizome Nine for the first time in ages, and she and Sigma had been discussing something together for the past few hours. Where Diana would have spent any other morning in the laboratory with Sigma, helping him with the equipment and explaining what all the chemicals he'd been instructed to make were used for, she basically had nothing to do.

So she'd come over to the lounge which, other than Sigma's own office and the crew cabins, had to be the most liveable place in the facility. It was a place where she could try and just relax. Mostly. Once again, that niggling feeling that she'd been somewhere like this before, and been afraid there, had sprouted up again.

Hadn't Zero II's underground bunker had a lounge sort-of-similar to this one? It had, hadn't it? But why would Diana keep associating the place where Sigma and she had finally found a home with that awful place?

Diana was distracted from that thought as someone entered. It was a robot – a 'Gaulem', Sigma had called them when he'd first shown Diana his designs for them – carrying a tower of crates filled with bottles stacked a couple of levels higher than would have been entirely sensible for a human trying the same thing. The robot had no trouble though, even with the stack blocking his eyes; he was able to first place them on the end of the bar then quickly and efficiently unstack them. He headed round to the other side to start unloading them onto the bar's shelves, which was when he first noticed Diana watching him.

"Eyup! It's the Missus!" he cried out. He mimed like he was doffing a flat-cap. "GTM-CM-G-OLM, at your service, madam! Well, I have to get this delivery sorted first, of course. Wouldn't want to let these beauties rot away on Miss Akane's shuttle, would we?"

Diana was taken aback. She'd known that the Gaulems had been programmed with intense personalities and she'd been ready for that. But… "I'm… 'the Missus'?" she had to ask.

"Course you are!" The Gaulem tilted his head in what Diana could tell was his best impression of a wink with his unblinkable eyes. "Me and my mates may just be soulless steel, but even we can tell that Master Sigma's got all the turtle dove f'you that you've got for him. And can I say, we're all rooting for you. All us Gaulems. Right down to the baselines of our code on that quantum computer Master Sigma's just spun up."

It had been three years since Diana had first made her way to Rhizome Nine. She still had never worked up the courage to say it. "You think I should tell him?"

"Of course you should! I'd never forgive myself if I let you let a chance like this slip," GTM-CM-G-OLM said. He took a couple of side-steps until he was at Diana's end of the bar then ripped open the closest box. "How about a bit of Dutch courage to get you going?" he offered.

Diana nodded gratefully, stood up and headed over to the bar. A small tumbler was placed on the counter in front of her, then a bottle of purple liquid was given to her alongside it. Diana inspected it warily. "What is this?" she asked.

"Hell if I know," GTM-CM-G-OLM replied. "I was programmed as a philosopher, not a publican. I couldn't even do a taste-test for you; just grabbed the first bottle of booze on top."

Diana tilted the bottle and peered at the label. "It says it's a bottle of 'Moon Alcohol'." What sort of company would market their produce as just 'alcohol', not a specific type? "Is this something that was made after the world ended?" Diana asked GTM-CM-G-OLM.

"Oh!" GTM-CM-G-OLM straightened up, the tone of his voice conveying his sudden realisation. "I know what these are for. That's why Miss Akane brought them up now."

"What are they?"

"These are the special bottles, right?" GTM-CM-G-OLM explained. "The one for the Lounge puzzle Master Sigma needs to set up. You know, on the Master's behalf, we've gotta thank you for helping him along like this. He wouldn't have gotten anywhere yet if you weren't looking out for him."

Wait, what? Why was Sigma setting up puzzles? Why were he and Akane treating puzzles as so crucial?

"Well, it's for the game! The what's-it-called: Nonary Game. Isn't it?" GTM-CM-G-OLM exclaimed. "Bunch-a folks are gonna come right through here and they're gonna need to solve the puzzle to get out again. Tons of symbolism, of course. If it's down to me, I think eclipse theme he's got for this one in the Lounge is right clever."

No. It couldn't… no. "What… What is this Nonary Game?" Diana forced out.

"I don't know everything: that's up to Master Sigma," GTM-CM-G-OLM said, completely oblivious to Diana's distress. "But from what I've heard, the players need to get through the puzzles as quickly as possible to get to the other side. That'll give them an advantage on the main game to get out of here. Everyone who wins gets out, and those who don't get stuck here. Oh, and in certain rooms doing the puzzle properly gets you extra bonuses. I know I've got some stuff in my code for if the contestants get to me. I've been greatly bloody honoured, if you ask me. But yes, the main deal is getting out or not."

No.

"You got any ideas for it, Missus?" GTM-CM-G-OLM asked. "I know the Master's said that most of it is set in stone, but Miss Akane sent you up for a reason. My mates and I, we're all looking forward to what you add to this."

No… It couldn't… Sigma couldn't be… "This is a death game, isn't it?" Diana stated. Just like Zero II's. Was that why everything felt so reminiscent of Zero II's bunker.

"Guess you could say…" GTM-CM-G-OLM caught himself, shaking his head and waving his arms. "No. Don't say it like that. It's presumptive of me to say this to you, I know, but your words for it are loads harsh. It's really just…"

Diana didn't hear the end of what GTM-CM-G-OLM had to say. Anything else, she'd have to hear from Sigma himself. It was the only way she could stop her heart from breaking entirely.

o-0-O-0-o

GTM-CM-G-OLM had said that Sigma was working on the quantum computer. That meant he was in the Q room. Diana raced there, barely feeling one foot landing in front of the other.

When she arrived, Sigma was there as she expected, bent over the control panel of the computer that had been installed there. Diana couldn't say that was a good thing. Her entire body was screaming at her to put it off, to confront Sigma some other time, or some other time after that. But she was there now, and Sigma was there now. She had to ask.

"Sigma! Sigma… Why are you making a death game? Why are we making a death game?"

Sigma stood up from the console and took a deep breath. "You found out." It was a cold, hard statement.

"How did you hide this from me for so long?" Diana asked, her hands shaking. "Was it all an act? Then and now? Is this what you're really like? Like Zero II?"

A pained expression contorted Sigma's face. "It's not like that. This is really important. If I can't do this, then…"

"Are you going to put those poor people I saw with Phi through this?" When Sigma didn't reply immediately, another horrifying possibility rose in Diana's mind. "Not Phi too?"

Sigma's head fell. "I'm sorry, Diana."

Something inside Diana broke. Three years. Three years she'd spent, all for this. "Sigma, I… I…" Her vision was going blank. She couldn't think. "Sigma, I…"

And then her knees gave way and she fell into Sigma's arms.


	6. Chaser to the Soul

_Earlier…_

"So what's making this so complicated?" Sigma asked Akane.

Akane smiled knowingly, not the first time since she'd arrived at Rhizome Nine that morning. "There have only been eighteen antimatter reactors before now. It's hardly as though we have exhaustive knowledge of every last hurdle in their operation. And, as you know, the track record of the first eighteen is hardly ideal."

Of course. Sigma had seen the destruction caused by the first eighteen. It was the first thing Akane had showed him back in the past, for precisely the reason she was leveraging now. "So we have to be careful. You wouldn't be making such a big deal about this if it was just that."

"It turns out," Akane said, shrugging, "that the only thing capable of tracking everything involved in an antimatter reactor initiation is a quantum supercomputer."

"But you told me that our quantum computer could only be powered by the antimatter reactor!" Sigma snapped. Then he realised what Akane was implying and sighed. "Goddamnit."

"Quite the paradox, don't you agree?" Akane said wistfully. "We know that both computer and reactor will eventually be set up, of course. And neither of us will have many more resources available than we do now. So I figured we should have a go at it right now. It's delicate work – normally it would be attempted by a team of hundreds – but our special abilities should give us something of an edge."

"Okay. What's your plan?"

"We need to start them up in tandem," Akane said, gesturing at the Q room's console. "That way, when the critical stage comes the supercomputer will already be in position to alert us to any errors and correct them."

Sigma nodded, firmly. "So I'm manning one station while you manage the other, right? That's what your plan is."

"Exactly. It would certainly be for the best if I start the reactor and you monitor me from here. You've already made some progress designing the first Gaulem AIs, if I'm correct. In the event that there's nothing to worry about, you still won't have wasted your time; you can spend it uploading them."

Sigma had to agree. He'd gotten used to being bossed around by Akane, much his chagrin.

"Okay," Akane concluded, "Give me twenty minutes to head to the Control Room and activate the reactor. After that, the computer here should become operable. From there: do your best, Sigma. You know as well as I do that the entire future depends on this."

o-0-O-0-o

Sigma waited. At the time Akane had told him, the screen he'd been staring at sprung to life. Sigma quickly got to work. He'd expected a lot more fluctuations and crises from the reactor, but in reality the only one that really mattered was the power surge associated with the quantum computer itself. Once that was stabilised, the screen stopped blinking its warnings and Sigma went back to relaxing.

Akane had mentioned the Gaulem AIs so Sigma dealt with that next, just keeping the corner of his natural eye on the box that would bring up reactor warnings. He transferred the code for each of the Gaulems he'd designed from storage, then assigned each Gaulem one of the manufactured bodies. Then after checking that nothing had happened with the reactor while he was distracted, Sigma assigned them tasks. Akane had brought up more stuff from Earth than just the reactor, right? He might as well have that sorted out while he was tied up.

That only took up ten percent of the reactor's install time. So all Sigma had now was a tedious wait. It wasn't quite empty: there were further small surges when the antimatter reactor mistimed its takeover of the pantry, and a worrying drop in power when Akane overcompensated while powering the treatment centre. But for the most part Sigma was just wiling away the time.

And then the Q room's door slid in behind him and someone rushed in.

"Sigma! Sigma!"

o-0-O-0-o

"Why are you making a death game? Why are we making a death game?" Diana cried out.

Guilt lanced into Sigma. He'd not told Diana about the Nonary Game precisely because he'd guessed it would bring up bad memories of what she'd been through. Because he wouldn't have been able to face her if she knew. But now she knew.

"How did you hide this from me for so long? Was it all an act? Then and now?"

How could Sigma answer her? He'd been hoping so desperately that the forty years he'd have to prepare would whittle down his reticence. Did he have to confront it now? He… He couldn't.

"Are you going to put those poor people I saw with Phi through this?" Diana asked. Then, she asked, "Not Phi too?"

Sigma had only the truth to tell, in response to that. "I'm sorry, Diana." His mind spun imagining the consequences coming. Diana could have yelled at him; she could have just left Rhizome Nine, heading back to Earth never to return. But what happened next was worse. Diana let out a guttural broken gasp, and then collapsed.

Sigma caught her just in time and just too late.

o-0-O-0-o

"Why won't this work?!" Sigma cried out. He'd taken Diana to the fourth treatment pod that had been installed in the Botanical Garden, to no avail. The display just read 'Circulatory failure' and, as with Radical-6, refused to even try to treat it.

"Sigma…?" Diana whispered hoarsely as the pod lid opened again.

"Why won't it let me save you?!" Sigma yelled again. His heart couldn't deal with seeing Diana suffering like she was.

Diana grimaced as she tried to sit up, and failed. "I don't understand. If you're like Zero II, why would you do this for me. If you're… If you're the Sigma I knew, why… why a killing game, of all things? The world's ended: haven't we all suffered enough?"

"I can't let it end like this! I owe you at least an explanation. I owe you the chance to decide whether to forgive me or not."

Diana looked away, a tear forming in the corner of her eye. "I want to. I want to forgive Sigma. My Sigma. The Sigma who'd give forty-five years of his life to leap back in time and stop the end of the world."

"This is how that happens," Sigma murmured, not believing he had any right to be believed. "It's the Nonary Game that let's us go back to before the Mars Mission test. It was a death game; I can't deny it. And I made – am going to make – Phi, and Alice and Clover, and Junpei and his grandson, and my own son take part, just to make it work. Phi has to do it. And I had to do it myself. Because it was the only way we'd make it back in time to and try to stop Zero II."

Diana looked at Sigma. Sigma almost felt hope that he could see a spark of hope in Diana's eyes.

But before Diana could say anything – or maybe she did whisper something only to have it drowned out – a harsh voice blared through the loudspeaker.

"Sigma!" Akane snapped. "Sigma: why aren't you at the quantum computer? The next step is critical. Return to your station, right now!"

"That sounded… important," Diana forced out with all that was left of her strength. "You should… you should…"

o-0-O-0-o

Sigma walked through the doors out of the Botanical Garden.  
He carried Diana through the corridors, all the way to the Director's Office.  
He angled her around as manoeuvred a way through the hatch in the wall of the office.  
He laid Diana down in his own bed.

o-0-O-0-o

"Why did you bring me here?" Diana asked. Sigma could only hope that she was actually as comfortable as her serene face looked.

"You deserved it. You don't deserve to be left alone on a cold slab."

"But Akane's warning…"

"I made a choice. I made the right choice."

Diana smiled: faintly, but a smile. "That's the Sigma I know. It was nice… to see you again." She coughed, weakly, and began to fall asleep, murmuring her final words as she went.

o-0-O-0-o

"This must be fate."  
"I've wanted to come here, ever since I was little, so I'm perfectly fine with dying here."  
"I'm in love with you."  
"It must be a wonderful future. The future where we found each other…"

o-0-O-0-o

When he could finally stand again under his own will – he couldn't have said how long it had taken – Sigma stumbled his way back to the Q room. Akane was already there.

"Sigma!" she snapped. "I told you how important this was! If even the slightest little error had happened while you weren't here, the entire AB project –"

"Diana died," Sigma stated bitterly. "She died just now."

Akane at least had enough respect to bow her head. "So today was that day?"

"You didn't know? You sure like acting as though you know everything."

"Not this." Akane shook her head. "Even if you don't trust me on this, there's no reason why I would have purposefully chosen to schedule the reactor start on the same day. Do you think I'm insane? You know that I wouldn't have wanted something like this to blow up Rhizome Nine."

Sigma scoffed. "Maybe in ten years, I'll have calmed down. Maybe ten years after that. Maybe. Don't come back up here before then. Whatever the emergency, whatever you think you have to say to me. Don't rub this damn thing in my face. For now, as far as I'm concerned, you could have easily figured it would be just fine to do it like this.

"After all, even if something did go catastrophically wrong, wouldn't you just give up on this timeline entirely and jumped to one where I left Diana in the garden pod and helped you do your thing instead?"

Sigma turned and strode away, out of the Q room as fast as he could. As he walked, he only just caught Akane's parting murmur.

"There wasn't even one timeline where that happened. You know that, just as well as I."


	7. Six Billion Footprints on Planet Earth

_Epilogue._

"You ready?" Phi said to Sigma, as they stood on the door step of the building where the Mars Mission participants were to meet before shipping out to the desert. "You'd better be. We've gone through too much to screw up now."

"Of course I am," Sigma replied. He'd had forty-five years to prepare for this moment. With all that experience behind him he stepped forward, turned the handle, and opened the door.

They walked in to see a receptionist. The receptionist looked up as they approached. He recognised them – maybe a bit too quickly, but Phi and Sigma had both provided identification photos a while beforehand so it wasn't too weird that he knew them by sight – and waved them on into the next room. They headed on.

There were only two people – other participants – in that room when they entered. One was an extraordinarily old man, sitting almost motionless in his wheelchair and drinking a glass of water only with considerable help. And the kind young lady giving that help was…

Diana.

"Dia –!"

Sigma almost called out her name, so many decades of emotion catching up with him, and he was stopped only by a quick elbow in the side from Phi. Caught in the act, he managed to recall how flustered he'd been when Diana had known him and he hadn't known her. At least he had the advantage of knowing this was going to happen.

Thank Phi he'd been reminded to use that forewarn.

Instead he strode forward and introduced himself to her, as close to as if he had never met her before as he could.

"Hi! I'm Sigma. It's a pleasure to meet you."


End file.
